Thin-film transistors based on inkjet printed indium zinc tin oxide (IZTO) channel layers are reported in this paper. The printed IZTO transistor has a high field-effect mobility (µ_FE = ∼30 cm²V⁻¹ s⁻¹), excellent on-to-off current ratio (>1 × 10⁶) and behaves as an enhancement mode device (turn-on voltage = 2 V). This mobility is an order magnitude higher than previously reported for inkjet printed oxide-based transistors. The printed films are highly transparent in the UV-Visible regime with a transmittance higher than 95%. A transparent thin film transistor using a printed IZTO channel was also demonstrated for the first time.